1.0 Field of the Invention
The invention relates to an interface device for a telephone network that is used for testing the functionality of the telephone service supplier's telephone lines and, more particularly, to a network interface device that connects a telephone test instrument to the telephone lines of the central office.
2.0 Description of Related Art
Telephone networks are constantly increasing due to the ever increasing demands of the general public, as well as the demands of commercial and industrial establishments. Because of the enormity of the telephone networks, telephone equipment failures, as well as telephone lines servicing data communication equipment such as facsimile equipment and computers, sometimes occur, and because of the importance of these interconnected devices, these failures must be quickly localized and corrected.
Network interface devices for telephone networks are used in the functional testing of telephone service supplier's lines (versus telephone lines located within a building, which are usually maintained by the customers, and/or by the customers' telephone equipment supplier). The network interface device is typically located at a junction box where the lines from the telephone service supplier enter and are distributed throughout the building.
Network interface devices are known and one such device is commonly called a customer bridge. The customer bridge is located in the junction box and comprises a plug (male) and jack (female) mating arrangement in which the plug is connected, via cabling and wire wrap connections, to the customers' telephone lines. When the jack and plug are mated together, the customer bridge creates a continuous circuit between the central office and the customer's equipment. When a customer experiences a problem with the telephone lines, the customer can go to the junction box where the customer bridge is connected to test if the problem is with the telephone service supplier's lines or the telephone lines in the building of the customer. Underwriters Laboratories (UL) regulations require that anyone working on telephone lines at a junction box, such as the telephone lines associated with the customer bridge, create an open circuit, as presented to the customers' equipment, before even attempting to work on the telephone lines.
The customer bridge device is designed to require the removal of the plug from its mating with the jack, thereby opening the connection of the telephone lines of the telephone service supplier to the customer's telephone lines. The plug of the customer bridge must be disconnected before the associated plug of the test equipment is plugged in so as to check for the operation of the telephone lines of the central office of the telephone service supplier. Once the plug of the test equipment is installed, typically, if a dial tone is detected it signifies that the lines from the central office of the telephone service supplier to the building of the customer are working and the problem is in the telephone lines and/or equipment within the customer's building. Although the customer bridge serves well its intended purpose, it does suffer the disadvantage of requiring a plug, along with cabling and wire-wrap connections, for interconnecting the customers' telephone lines which increase the cost of the customer bridge device and increase the chance of inadvertent malfunction.
Another problem associated with the customer bridge commonly occurs when a customer works on telephone wires, e.g., to remove, clean or repair telephone wires. More particularly, the customer bridge is commonly utilized and it is done so without disconnecting the plug of the customer bridge despite posted warning of such an undesired operation. It is desired that means be provided that disconnects the telephone lines of a customer from the telephone lines of the telephone service supplier during testing of those lines without relying on the need of any separate and affirmative removal of the plug of the customer bridge by the customer.
Therefore, there is a need for a network interface device that eliminates a plug, cabling and wire wrap connections for interfacing the customer lines to the telephone lines of the central office of the telephone service supplier.
Further, there is a need for a device that responds to the insertion therein of an associated plug of the telephone test equipment to automatically disconnects the customer telephone lines from the telephone lines of the central office of the telephone service supplier and, conversely, responds to the removal therefrom of the associated plug of the telephone test equipment to automatically connects the telephone lines of the customer to the telephone lines of the central office.